In an electron beam exposure apparatuses perform exposure in such a manner that an electron beam is emitted from an electron gun. The electron beam is let through a stencil mask with a rectangular aperture or an aperture having a predetermined pattern shape formed therein. Thereafter the electron beam is reduced in size at 1/20 for example by an electron optical system. Then the electron beam is projected onto a wafer.
For reducing the time required for the exposure, there is also proposed a multi-column type electron beam exposure apparatus which includes a plurality of electron beam columns (column cells), each of which a column cell is downsized and includes an electron gun and an electron optical system for projection of an electron beam. The multi-column electron beam exposure apparatus performs exposure in parallel using the plurality of column cells. Thus, the processing speed by the multi-column electron beam exposure apparatus is improved by a factor corresponding to the number of the electron beam columns, with respect to that of an electron beam exposure apparatus which uses a single column cell.
For further improving throughput, the number of column cells in the electron beam exposure apparatus is preferably increased, and further downsizing of the electron beam column is demanded.    PATENT DOCUMENT 1: Japanese Laid-open Patent Publication No. 2001-110351